1. Field of the Invention
The present invention relates to a communication system, a communication apparatus, a communication method for a communication apparatus, and a computer program.
2. Description of the Related Art
In the wireless LAN technology based on the IEEE802.11 standard, an increase in transmission rate has been achieved by the advent of an advanced version of IEEE802.11, such as IEEE802.11b or IEEE802.11g.
To support QoS (Quality of Service) for transmission of stream data, the IEEE802.11e standard has been established.
In the IEEE802.11 wireless LAN standards, two communication modes are allowed. In an infrastructure mode, wireless communication stations (hereinafter referred to as STA's) communicate with each other via a base station called an access point (hereafter referred to as an AP). In an ad hoc mode, two STAs are allowed to directly communicate with each other.
In the IEEE802.11e standard, DLS (Direct Link Set-up) is defined for direct communication between STAs under control of an AP in the infrastructure mode.
In general, direct communication between STAs is more efficient than indirect communication via an AP. Additional efficiency is desirable in particular in transmission of stream data.
For further detailed descriptions, see, for example, Japanese Patent Laid-Open No. 11-275106, Japanese Patent Laid-Open No. 2004-266653, or Japanese Patent Laid-Open No. 2005-323346.
In conventional techniques, to switch a plurality of communication apparatus communicating with each other in the infrastructure mode into the ad hoc mode, a user has to perform an operation using a setting application program or the like to switch the mode for each communication apparatus. This is very inconvenient for users.
In direction communication using the DLS, if a communication band available on an existence network becomes insufficient, it is impossible to control communication band based on the QoS.